"A few weeks ago I got my Pi delivered and started working on what I would describe as 'universal console'. In this post I describe my initial thoughts about this project and present an adapter that allows you to use SNES controllers as input devices for the Raspberry Pi." This is what the Pi is all about. Amazing work by Florian (can't find his last name!), code and instructions are available. So cool.

Who knows how reliably you could differentiate between ZSNES or SNES9x on one side, and bsnes or MESS on the other, with most titles ...while in a properly set up blind test ;p
ZSNES was quite accurate for a long time, while not requiring powerful hardware at all (IIRC, some fast 486 could do)

What's more often missing IMHO is not the console side, but the display: after all, old-school consoles were played on interlaced CRT TVs - that was the norm up until (and mostly including) PS2 generation. And the very nature of those CRT displays applied a filter of sorts, some kind of hardware anti-aliasing, which is largely neglected under emulators (they often do have some filters, but typically without much attention given to them).
Perhaps we need serious project to emulate few standard kinds of TVs, to be used by display layer of gaming emulators

That said, I do value pursuits of low-level emulation, in context of such gaming accuracy, because they partly push aside the drive to "enhance" games.
A drive which doesn't end up so bad in the case of SNES (with "2D" scaling filters such as 2×SaI or hq2x - and indeed, bsnes includes such).
But it IMHO gives quite atrocious results with PS1 for example, where that "CRT anti-aliasing" (coupled with skilful use of dithering, also blended a bit by the TV) ...are replaced by simplistic blowing up of resolution & colour palette, and blurring textures into total soap (like in the worst of Voodoo 1 era PC games) - and many people seem to honestly think it's better like that O_o (me, I prefer an "aesthetic cohesion" of sorts, at which many of the best PS1 games clearly aimed - and not only them of course, Starcraft or Homeworld also display it for example)